Which seems like a good idea to me, except for the following list of requirements..
Will it run window's apps? You are doing to have to support running miscellaneous windows applications fairly well, up front. Things like Turbo Tax, Quicken, old games and the like will just need to work, out of the box, and not require special knowledge to install. Dorking around with Wine should NOT be required.
What apps will it come with? It's going to need to have a fairly complete stable of applications, starting with Office. They are going to need to look and feel almost exactly like Microsoft's offerings and do everything Office does and more.
Will it infringe on somebodies IP? I'm sure Microsoft has some kind of IP or patent on the look and feel or something they can use to drag the project over the coals and kill it.
If you do this, PLEASE use Apache licensed stuff!